Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only cover read-only and closed-world; the description adds substantial context beyond that: results are capped but return the true count, service items and placeholder SKUs are excluded, the filter mirrors the dashboard chip's rule, and Counter/till companies report quantities as of last day-close. That last note materially affects how an agent should interpret the numbers.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The core answer is front-loaded in the first clause and the row shape follows immediately. The closing Counter/till paragraph is long, but it carries real interpretive value rather than restating the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description supplies the row fields (sku, name, on-hand, reorder point, unit), the truncation behavior plus true count, and the exclusion and timing caveats. An agent has everything needed to call it and to narrate the result correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing to disambiguate; baseline 4 applies. The description spends its words on result semantics instead, which is the right allocation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Names the exact resource and filter in one stroke: "products at or below their reorder point right now" plus the colloquial framing "what do I need to reorder". This clearly separates it from stock_level (all levels) and stock_movements (history) without needing to open either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a strong usage context (the reorder-decision list) and implicitly positions itself against level/movement siblings via "right now" and "at or below". It does not explicitly name when to prefer stock_level or stock_movements instead, so it falls short of a full when/when-not/alternatives statement.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.